In endoscopic examinations/procedures, flexible instruments designed to view the gastro-intestinal tract are inserted along a body cavity to an internal part such as the stomach, duodenum, small intestine or large intestine. The instruments are provided with fibre-optic or charge-couple device (CCD) cameras which enable images to be transmitted around bends and images to be produced to displays on a television screen. Accordingly, it is possible to view the inside surfaces of the oesophagus, stomach and duodenum using a gastroscope, the small intestine with an enteroscope, part of the colon using a flexible sigmoidoscope and the whole of the large intestine (the bowel) with a colonoscope.
Enteroscopy is the endoscopic examination of the small intestine whereas colonoscopy is the endoscopic examination of the colon and the distal part of the small bowel and flexible sigmoidoscopy is the examination of the rectum and lower part of the bowel. Each scoping procedure may provide a visual diagnosis (e.g. ulceration, polyps) and grants the opportunity for biopsy or removal of suspected lesions. Whilst colonoscopic and enteroscopic examinations are the most effective techniques to assess the state of health of the bowel, they are inconvenient, uncomfortable, expensive procedures that are associated with significant risks of potentially serious complications. The most common complications are: failure to achieve a complete examination (5-10%); failure to detect a polyp (up to 20%); reaction to intravenous drugs; over-sedation leading to hypoxia and cardio-vascular collapse; splenic injury (rare); bowel perforation, (1 in 500-1500); full thickness burn (uncommon) and; bleeding following polypectomy.
A further disadvantage of colonoscopic and enteroscopic procedures is that they are time consuming for patients and medical personnel alike, the procedure can take anywhere from 20 minutes to 2 hours depending on how difficult it is to advance a scope through the colon or small intestine. The colonoscopy itself takes around thirty minutes to perform but in some cases may require up to an hour, and for the patient, there is a recovery period of up to two hours in hospital whilst sedation passes off and over that time clinical observation is needed. Typically, the number of clinically competent personnel required to conduct a colonoscopic procedure are an endoscopist specialist and three assistants including the person responsible for reprocessing the equipment. In addition, staffing is required for the recovery area.
Two yet further additional significant difficulties associated with colonoscopy and scoping procedures more generally are as follows:
Firstly, the anatomy of the colon is such that the lining is thrown into folds. As the tip of the endoscope passes along the lumen of the colon, these folds hamper the endoscopist's ability to visualise the entire surface of the mucosa and in particular, detect pre-malignant and malignant lesions tucked away on the proximal face of these folds during extubation.
Secondly, the position of the tip of may be difficult to maintain from the moment at which a lesion or polyp is detected to the completion of any therapeutic procedure. As the colonoscope is withdrawn the tip does not travel back at a constant speed but rather with jerks and slippages particularly when traversing a bend or length of colon where the bowel has been concertinaed over the endoscope shaft during intubation. The tip of the device may, at any moment, slip backwards thereby causing the clinician to lose position. If tip position is lost, the clinician is required to relocate the lesion or polyp for the therapeutic procedure to be continued.
The colonoscopic procedure is not simple because the bowel is long and convoluted. In places it is tethered by peritoneal bands and in others it lies relatively free. When the tip of the endoscope encounters a tight bend the free part of the colon “loops” as more of the endoscope is introduced and so looping occurs in the free part of the colon before the bend when there is difficulty negotiating the bend. This leads to stretching of the mesentery of the loop (the tissue that carries the nerves and blood vessels to the bowel). If the stretching is continued or severe while the endoscopist pushes round the bend, the patient experiences pain the blood pressure falls and the pulse slows. Loop formation is the main cause of failure or delay in completing an examination. It is responsible for the pain experienced by the patient and the need for heavy sedation that in turn leads to cardio-respiratory complications. It is also the major cause of perforation in patients not undergoing a therapeutic procedure.
Attempts have been made to try to overcome the problems associated with colonoscopic procedures, for example, it is known in the prior art to provide endoscope sheaths having differential frictional resistance provided by very small external protrusions such as wedge-shaped profiles or scales so there is low frictional resistance during forward movement of the covered endoscope shaft through a body cavity and a greater frictional resistance during its rearward movement. In practice however little improvement is achieved in overcoming looping. It is also known from the prior art to use a double balloon enteroscope or an Aer-O-Scope™. The double balloon enteroscope requires a substantial amount of additional kit, a high level of operator skill in timing the sequential inflation and deflation of the balloons and moreover it is a lengthy procedure sometimes taking hours. The Aer-O-Scope™ provides low pressure colon insufflations with CO2 to propel the balloon along “slippery” colon walls without forceful manoeuvring but cannot be used for biopsy or therapy.
Despite the forgoing drawbacks, for the foreseeable future colonoscopy will remain the procedure of choice for the examination of the large bowel. Newer methods for the detection of polyps and cancer using non-invasive technology may be identified but to obtain biopsies, remove polyps and to treat intra-colonic lesions no alternatives have appeared to date.
An improved medical scoping device that could reduce the time taken for the colonoscopist or enteroscopist to perform the procedure would offer immediate advantages to patients and clinicians alike.
An improved medical scoping device that could reduce the risk of complications during a procedure would offer immediate advantages to patients and clinicians alike.
A medical scoping device that could improve endoscopic intubation, extubation and visualisation of the large bowel would offer immediate advantages to both patients and clinicians alike.
A medical scoping device that could reduce loss of tip position during a medical procedure would offer immediate advantages to both patients and clinicians alike.
An improved medical scoping device that could reduce the requirement or level of sedation for a patient would offer immediate advantages to both patients and clinicians alike.
An improved medical scoping device that could overcome the problems associated with looping and so reduce discomfort to the person on whom the procedure was being performed, would offer immediate advantages to patients and clinicians alike.